#include<stdio.h>
int main()
{
	double arr[10] = { 0.0 };
	double sum = 0.0;
	double average = 0.0;
	for (int i = 0; i < 10; i++)
	{
		scanf_s("%lf", &arr[i]);
	}
	for (int i = 0; i < 10; i++)
	{
		sum = sum + arr[i];
	}
	average = sum / 10.0;
	printf("%lf", average);
	return 0;
}